The present disclosure relates to a rotary-cutting disk having a draining duct for a liquid phase from a centrifuge, particularly from a separator.
Rotary-cutting disks—also called grippers—for centrifuges are known in many different embodiments such as from U.S. Patent Document U.S. Pat. No. 2,667,338. It is their object to drain a liquid phase from a centrifuge. Because of the type of their construction, many of the known solutions require high expenditures for their manufacture. Examples of this type are shown in European Patent Document EP 0 892 680 B 1, International Patent Document PCT/SE88/00181, U.S. Patent Document U.S. Pat. No. 4,406,652, U.S. Patent Document U.S. Pat. No. 2,230,210 or European Patent Document EP 0 756 523 B1.
British Patent Document GB 987023 and European Patent Document EP 0 756 523 are also mentioned with respect to the state of the art.
In practice, depending on the number of liquid phases to be drained, one or more of the rotary-cutting disks are arranged concentrically with respect to the axis of rotation of the centrifuge. Thus, it is known, for example, to place the rotary-cutting disks onto an intake tube of a separator. Furthermore, generally, the rotary-cutting disks have a disk-shaped or plate-shaped base section preferably adjoined by a tube-shaped section. They generally stand still relative to the rotating centrifuge. They have at least one draining duct by which liquid is again diverted from the inlet at the outer circumference of the disk-shaped section to the outlet in one or more axial draining duct/ducts in the tube-shaped section and, from there, the liquid is drained from the centrifuge. The at least one draining duct diverts the liquid in the disk-shaped section in the case of a known variant, for example, by slightly more than 90° from the flow direction at the outer circumference of the rotary-cutting disk in a curve toward the inside.
It is known to align the inlet of the draining duct at an acute angle with respect to the flow direction and to then lead it from the outer circumference of the rotary-cutting disk in a curve toward the inside.
This construction has been successful per se. However, the effect of cavitation has been a problem. It is desirable to reduce the effect of the cavitation and to also reduce stimulation of liquid-excited vibrations.